Why are you booing Vernon Wells?

Somebody told me the fans around him were booing Vernon Wells as early as Saturday, but I didn't hear it where I was sitting. Then Bill told me there were some boos on Sunday. And last night, after he struck out in his third at bat, the boos were quite clear, especially coming from the right-field side of the park. And after he popped up in the ninth, they were even louder.